The name Perpetual Groove indicates a stylistic form for the veteran jam band. You hear the name and imagine long songs segueing through jams from one to the other. In a sense, Perpetual Groove could define many jam bands, but with PGroove, you get the name, and an assortment of various musical tastes and styles that careen from the stage like a robotic factory on overdrive.

Perpetual Groove is first and foremost a jam band in the eyes of crowds and talent buyers. The band came together in Savannah, Georgia before relocating to Athens, Georgia, a haven for live music and home to the Georgia Theatre, both before and after the catastrophic fire that leveled the historic venue to ashes. Always heralded as a locale for jam bands, Perpetual Groove built a repertoire in Athens and ran with it, traveling the country year after year, tour after tour, expanding a responsive fan base that stretches far from the cushy confines of the southeast.

It seems PGroove finds their way to Colorado every winter for a few shows along the Front Range, and the Fox Theatre is among the venues most frequented since they first took the stage there in 2004. Having seen the band over a dozen times, I have fortunately been able to catch them perform six times at the Fox as a patron, an intern, and a stage manager. Each experience has been significant in my growth of appreciation for the band and their expansive songbook of covers and self-penned melodies. This show was no different, as they blitzed through gear shattering songs connected by endlessly running and well-greased transitions.

Boulder locals Springdale Quartet warmed up the room to few bodies but nonetheless proved that you treat every show as a sellout. Looking fresh in their Sunday best, the guys launched into a funky, danceable, organ driven remedy for the bone chilled patrons still wrapped in their coats. It was as if someone let Booker T and Jimmy Smith commandeer a ballpark organ and a rock and roll band. They showed their mettle through thick bass lines complementing the organ and steady drive of fill-in drummer Adam Segalis of Denver’s own Recovery Act. Being able to see these guys play a place like Boulder’s Conor O'neill’s to this day is almost too good to be true, as they seem set on climbing higher in the ranks of Colorado’s music society. Guitarist Ben Waligoske welcomed vocalist Lindsay French, also of the Recovery Act, to shine upon the final number, Etta James’ “I’d Rather Go Bind,” before clearing their Hammond side stage. Their debut album, “Noisefactory” was released last year.

By the time guitarist Brock Butler stepped on stage to adjust his world of axes, the crowd had nearly tripled. The room can be deceiving, but there was no doubting the momentum their past shows in Boulder carried. There were spinsters, tricksters, beards and booty shorts; the eclectic jam audience showed up. Brock even took a timeout during the first set, telling the crowd that it’s always something special in Boulder, and that they hope the fans in the crowd realize that they always give it their best when they’re at the Fox. His praise did not fall on deaf ears.

Bassist Adam Perry kicked off the first set with his stylistic swagger of lines dipping in and out as the other instruments came to life. Wearing sunglasses, Adam stared towards the ceiling and bright lights, thumping the place. Brock’s guitar sent shivers through the crowd as the hoots and hollers multiplied to the post-apocalyptic sound slowly building before bursting through the seams, only to mellow again, building upon a series of notes and familiar territory. The first song to take form, “Mota,” is very characteristic of Perpetual Groove and the nature of their sound. Lacking vocals, the song reinforces the bands’ name as it builds and builds before breaking like a three-day fever to the delight of the sweaty dancers convulsing with each chord.

The essence of the first set can be described as dark and wicked. The songs developed and bled into one another seamlessly. Some have described PGroove’s sound as arena rock, which can be heard as Brock solos through his mixes of distortion and tone altering pedals. Sometimes their shows can be light and uplifting, and while there were elements of that, this show carried the torch lit from the flames of Hell. The moody, dark stage blitzed with lights seething through streams of cables and gaff tape created a mood that was reinforced by the music.

Once the set started, the crowd was locked into the syncopated rhythm between the drums and bass. Albert Suttle has been silently moving the band for years, providing much more than what meets the eyes and ears. He keeps the band moving, and he and Adam seem to alternate between being the driving force while Brock dances his leading notes and keyboardist Matt McDonald engineers a synth symphony in his own corner of keyboards world. McDonald, who departed the band in 2008, is now been back with the guys, and judging from the sounds they created, the time off allowed him a chance to reevaluate the band from his skill set and reconnect with them on a deeper level than ever before.

The darker, metallic jams gave way to the first cover of the evening, as the Johnny Cash tune “God is Going to Cut You Down” burst through the seams. This was the perfect addition to the set and gave Brock a chance to flex the vocals he’s held down for as long as they’ve been together. This to me represented a theme to the first set, where sin, darkness, and ghastly jams that are defining many of their recent shows flourished. This being said, they brought the first set back to their lighthearted selves with the title track from their first album, the classic, “Sweet Oblivious Antidote.” This song is the epitome of early PGroove. While the show was primarily filled with darker jams and numbers, this song showed what they have been and how far they’ve come both in their playing and songwriting. They’re a band with many options in their playbook, which makes the live performance all the more entertaining since you don’t know what show you’ll see on any given evening. While the tune still has the loping bass and drum combo, the music is much more uplifting, with Brock’s guitar shining like a rising sun in cahoots with his mystical lyrics. It provided a great change of pace for the first set, and many people could be heard saying that that’s the PGroove they know and love. I myself enjoy every curve ball they throw my way.

The second set was full of material that appeased both fans of their older work and the newer material. Kicking it off was “Cairo,” which really shows their growth as a band. It starts with a break beat by Albert, and really comes together like some of the earlier songs, where synth and guitar make you feel like you’re floating around the sky with the bass pushing you onward. Some excellent vocals by Brock lead them into a jam that goes into many musical directions. The melody on this track is very soothing and makes you feel like you could be in the middle of meditating as they drift through their parts. The jam gave way to one of my absolute favorite Perpetual Groove numbers from “Sweet Oblivious Antidote,” “Sundog.” It starts with Brock running up and down the fret board, working note after note, as gentle piano accompanies before the rhythm section knocks the restraints off and the band erupts into an electric hoedown that leaves me spinning in circles everytime.

“Sundog” embodies what I love about PGroove: they start with a basic song structure and while deliberately investigating every nook and cranny, they develop a rapport that drives them far out of the confines of your usual song. This is their bread and butter, and while some call them a jam band, I call them Perpetual Groove. It really is always a process through which their songs expand during live shows. They aren’t simply jamming notes and chords that pop into their heads, but following a guideline that they’ve built over the years and simply expanding on it to greet the crowd desperate to dance. They do it as good as any band out there, and their love for Colorado and their fans is overwhelming sometimes. Building on Brock’s earlier comments of bringing it every time for the Fox Theatre and Colorado, Matt told us we were one of the best crowds and the best rooms for a concert in the country. With that heaping of support from the band, they launched into a cover of the KC and the Sunshine Band staple, “Get Down Tonight,” and oh how we did.

They encored with a rocking rendition of Rage Against The Machine’s “Sleep Now in the Fire,” with Brock handing over the guitar work to Matt and rapping with the crowd as he shouted the lyrics to the delight of the crowd.

In the end, Perpetual Groove brought their A game to the Fox Theatre. Their unique blend of rock was captured and highlighted each era of their fifteen years together on the road and in the studio. With the full-fledged return of Matt to the band, their spirits are high and their creative output is pouring through. The Boulder faithful is lucky to have a band as eager as PGroove is to bring their jams to town every year, and when they attend the show, they make their appreciation known.